feat: Implement backend API and basic frontend structure

Adds initial backend API endpoints for fetching users and attendances, including basic filtering. Sets up the frontend routing with a layout component and includes placeholder pages for dashboard, users, and login. Refactors the README for local development setup.

App.tsx

@@ -0,0 +1,43 @@
+import React from 'react';
+import { HashRouter as Router, Routes, Route, Navigate, useLocation } from 'react-router-dom';
+import { Layout } from './components/Layout';
+import { Dashboard } from './pages/Dashboard';
+import { UserDetail } from './pages/UserDetail';
+import { AttendanceDetail } from './pages/AttendanceDetail';
+import { SuperAdmin } from './pages/SuperAdmin';
+import { TeamManagement } from './pages/TeamManagement';
+import { Login } from './pages/Login';
+import { UserProfile } from './pages/UserProfile';
+
+const AppLayout: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const location = useLocation();
+  const isLoginPage = location.pathname === '/login';
+
+  if (isLoginPage) {
+    return <>{children}</>;
+  }
+
+  return <Layout>{children}</Layout>;
+};
+
+const App: React.FC = () => {
+  return (
+    <Router>
+      <AppLayout>
+        <Routes>
+          <Route path="/login" element={<Login />} />
+          <Route path="/" element={<Dashboard />} />
+          <Route path="/users" element={<Navigate to="/admin/users" replace />} />
+          <Route path="/admin/users" element={<TeamManagement />} />
+          <Route path="/users/:id" element={<UserDetail />} />
+          <Route path="/attendances/:id" element={<AttendanceDetail />} />
+          <Route path="/super-admin" element={<SuperAdmin />} />
+          <Route path="/profile" element={<UserProfile />} />
+          <Route path="*" element={<Navigate to="/" replace />} />
+        </Routes>
+      </AppLayout>
+    </Router>
+  );
+};
+
+export default App;